Intradiscal vacuum phenomenon is commonly shown in radiographic studies of the degenerative spine. In terms of pathophysiology, intradiscal gas migrates to the epidural space, and then it could compress neural tissues and lead to severe radicular pain and/or neurologic deficits. Herein, we report two patients with lumbar radiculopathy resulting from gas-containing pseudocysts at the L5-S1 space, including our treatment and literature review. One patient had been underwent L5-S1 partial laminectomy and removal of the gas-containing pseudocyst, and the other underwent right selective L5 root block. After the procedures, they didn’t have any remarkable complaints. In the present study, we suggest that surgical decompression may be effective in patients who were untreatable with conservative treatment.
Intradiscal vacuum phenomenon represents collection of gas into the intervertebral disc space. It is a relatively common radiologic finding [
However, gas-containing pseudocysts causing lumbar radiculopathy are relatively rare [
We report two patients with radiculopathy resulting from gas-containing pseudocysts on the L5-S1 space. In addition, we report the diagnostic tool and treatment options of symptomatic epidural gas-containing pseudocyst based on our cases with review of previous studies.
A 74-year-old female patient with a 5-month history of right leg radiating pain on posterior aspect admitted to our clinic. She had difficulty in lying and walking due to the severe leg pain. She had presented poor response after 5 months of conservative treatment at other hospital. The pain and sensory deficit were localized to right S1 sensory dermatome. VAS (visual analogue scale) score for leg pain was 8 points. Physical examination revealed the weakness of plantar flexion of right great toe (Medical Research Council power Grade 4/5). Electromyography and nerve conduction study showed the radiculopathy of right S1 dermatome.
On MRI, the lesion was located on ventral side of L5-S1 spinal canal (subarticular area). It was oval shape with homogenous hypo-intensity on T1- and T2-weighted images. Computed tomography (CT) scan also revealed intradiscal vacuum phenomenon on L4-5 and L5-S1 levels. The lesion was hypodense and could be diagnosed as an epidural gas-containing lesion (
A 69-year-old female patient with a 3-month history of right leg radiating pain was admitted to our medical center. The pain and sensory deficit were localized to right L5 sensory dermatome. Dorsiflexion strength of right great toe was slightly decreased (Grade 4+/5). Twenty months ago, she was underwent decompressive laminectomy for severe stenosis at L3-4 and L4-5 level in other hospital.
On MRI, oval shaped lesions were located on both intervertebral foramina at L5-S1 level. It was homogenous hypo-intensity on T1- and T2-weighted images. CT scan revealed vacuum phenomenon, the right one was larger than the left. The lesion was hypodense and could be diagnosed as an epidural gas-containing lesion (
Gas collections have been described in literatures regardless of spinal segment, including the disc space, vertebral structure, epidural and intradural spaces, synovial cysts and facet joints [
Intradiscal gas might migrate to the epidural space, and herniated intraspinal gas could form the lesion [
Treatment options for epidural pneumatic pseudocyst are still not established. Anda et al. [
However, invasive procedures were required in cases that had severe pain with neurologic deficits, refractory to conservative therapies. Invasive treatments for gas-containing pseudocyst such as needle aspiration and operation had been reported [
In the present study, we suggest that lumbar gas-containing pseudocysts could induce radicular pain and/or symptoms of neurologic compromise. The gas-containing pseudocysts of two patients in our case were not spontaneously absorbed and caused radicular pain for a long time. Therefore, we suggest that surgical decompression may be effective in patients who were untreatable with conservative treatment.
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this manuscript.
Written informed consent was obtained from all patients for publication of this manuscript and any accompanying images.
74-year-old female patient with a 5-month history of right leg radiating pain. Axial Ⓐ and sagittal Ⓑ views on T1- and T2-weighted images demonstrate a hypo-intense lesion on MRI. Axial view Ⓒ of CT scan showing a hypodense lesion within the spinal canal at the L5-S1 level. Axial Ⓓ view on CT scan that had been examined 21 months ago.
Surgical findings showing gas-containing cyst lesion and foam, observing after gas-leakage Ⓐ. Cartilaginous thin membrane surrounding the gas was identified as the pseudocyst (Ⓑ, enlarged, ×200) in histopathologic sample.
69-year-old female patient with a 3-month history of right leg radiating pain. Axial Ⓐ and sagittal Ⓑ views on T1- and T2-weighted images demonstrate a hypo-intense lesion on MRI. Axial view Ⓒ of CT showing a hypodense lesion within the spinal canal at the L5-S1 level. Axial view Ⓓ on CT scan that had been examined 20 months ago.